A starter generator that is arranged in the auxiliary unit belt drive of an internal combustion engine causes, with its belt pulley alternately receiving and discharging torque, i.e., for a generator mode and a starter mode for the internal combustion engine, a corresponding switching of the tensioned section and slack section of the circulating belt. Therefore, the tensioning of the slack section requires a belt tensioner with two tensioning rollers that pretension the belt in front of and behind the belt pulley.
Known belt tensioners, as proposed, for example, in DE 199 26 615 A1, DE 10 2008 025 552 A1, and DE 10 2006 019 877 A1, each have a tensioner housing mounted on the starter generator and two tensioning levers that are supported so that they can move in this housing and whose tensioning rollers are moved by force toward each other by a spring element arranged there-between in order to tension the belt.
A belt tensioner according to the class is known from DE 10 2011 084 680 B3. This belt tensioner has a tensioning lever in the form of a tensioner housing that can be rotated by means of the belt pulley of the starter generator with a tensioning roller mounted fixed to the housing. The tensioner housing accommodates a bow spring and the other tensioning lever that can move against its spring force. For the simplest possible belt drive assembly, it is necessary that the two tensioning rollers are moved away from each other relative to their operating position and are locked in this set-apart position against the force of the spring that is greatly pretensioned in this position, in order to be able to place the belt during the initial assembly or to replace it in the event of servicing. The mutual locking of the two tensioning levers is realized by a securing pin that is then inserted into holes brought into alignment with each other in the tensioner housing and in the tensioner lever mounted in this housing.
Starting from this background, the present invention is based on the objective of improving a generator arrangement of the type named above and a belt tensioner for forming such a generator arrangement with respect to the belt drive assembly.